Method of and apparatus for compressing fluid



June 26, 1923. 1,460,645 R. SUCZEK METHOD OF AND APPARATUS FORCOMPRESSINGFLUID Original Filed May 13, 1921 xxx; 6' 6- 12 2 14 r 20 J T2 7: I

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' the nozzle structure,

ROBERT SUCZEK, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO C. H. WHEELERMANUFACTURING arm or PENNSYLVANIA.

COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORA- METHOD OF ANDAPPARATUS FOR COMPRESSING FLUID.

Application filed May 13, 1921, Serial No. 469,163. Renewed May 9, 1923.

To all whom it may concern:

Be it known that I, Ronnn'r Suoznx, a citizen of the Czecho-SlovakRepublic, residing in the city and county of Philadelphia, State ofPennsylvania, have invented certain new and useful Improvements inMethods of and Apparatus for Compressing Fluid, of which the followingis a specification.

My invention relates to a method of and apparatus for raising thepressure of or compressing elastic fluid, as gas, such as air, such assteam, or a mixture of gas or vapor, and vapor, by entraining the fluidto be compressed in a jet or jets of motive fluid,

more particularly gas, vapor, or a mixture of them, the mixture ofentrained and motive fluids then decreasing in velocity and increasingin pressure, as is characteristic of ejectors or aspirators.

In accordance with my invention, I procure greater efficiency ofoperation, either in single or multiple stage ejector apparatus, in thesense tion pressures greater amounts of fluid to be compressed arecompressed or raised to the desired pressure with less motive fluid.

In ejector apparatus in which the throat area of the nozzle structure isconstant and in which the ratio of the throat area of the nozzlestructure to the outlet area of the nozzle structure, that is, theexpansion ratio of the nozzle structure, is constant, and with a givenpressure of motive fluid supplied to the weight or amount of the fluidtobe compressed varies in predetermined way with regard to its initialor suction pressure. Accordingly, such arrangeme-nt is most effectivewith a given nozzle structure for a given suction pressure or initialpressure of the fluid to be compressed for compressing a maximum weightor amount of fluid. It is desirable, however, that the same ejectorapparatus shall be available to compress maximum weight or amount ofelastic; fluid with the same nozzle structure under conditions ofdifferent suction pressure or initial pressure of the fluid I to becompressed.

For this purpose I change or vary the pressure of the motive fluidsupplied to the nozzle structure, whereby greater amounts or weights offluid may be compressed from certain suction or initial pressures withthe that for different or varying sucinvention.

Fig. 3 is a fragmentary sectional view, on enlarged scale, of one of themotive fluid throttling devices.

Fig. 4 is a vertical sectional view,'partly in elevation, of a modifiedform of apparatus embodying my invention.

Referring first to Fig. 1, ordinates are pounds per hour of theentrained fluid or fluid to be compressed, and abscissee are absolutesuction pressures in inches of mercury column. The curve A is acharacteristic of a double stage ejector apparatus which may beemployed, for example, for maintaining high vacuum in a steam condenser.In the example illustrated the pressure of steam or motive fluidemployed upon the nozzle structure in both stages is approximately 125pounds per square inch. rom an inspection of this curve it is apparentthat the curve B is the characteristic for the same ejector apparatusemploying, however, motive fluid or steam at 100 pounds pressure asapplied to the nozzle structure of the first stage, while the steampressure applied to the nozzle structure of the second stage is 125pounds per square inch. characteristic for the case where the motivefluid or steam pressure applied to the nozzle structure of the firststage is 85 pounds per square inch, while, as before, the motive fluidapplied to the nozzle structure of the first stage is 125 pounds persquare inch.

From a comparison of these characteristics A, B and C, it is apparentthat while the curve A corresponds with better performance as to amountof fluid entrained and compressed at higher absolute suction pressures,the characteristics B and C show better performance in the sense ,thatgreater C is the amounts of fluid are entrained and compressed at therelatively lower suction or initial pressures of the fluid to beentrained and compressed.

To effect the performances illustrated by the above mentioned curves,the motive fluid pressure in the second stage may, in the examplediscussed, remain substantially constant, while the motive fluidpressures applied to the nozzle structure of the first stage areprogressively decreased as the first stage suction pressure decreases.By so decreasing the first stage motive fluid pressures for decreasedsuction pressures, the efficiency of the ejector apparatus is materiallyimproved in that not only are greater amounts of fluid entrained andcompressed, but with less expenditure of motive fluid.

These changes of pressure of motive fluid upon the nozzle structure areeffected by employingsuitable motive fluid throttling devices, asnozzles or orifices, or valve structures having known or predeterminedsettings.

By preference, and in the examples herein illustrated, the means forthrottling the motive fluid is a nozzle or orifice of fixedorpredetermined capacity.

Referring to Fig. 2, E and E are ejectors of any suitable types orstructures of which E may directly discharge into the ejector E or, aspreferred and illustrated, there may intervene between them theinterstage condenser C, wherein the motive fluid or other condensablevapors discharged by the ejector E are condensed, leaving only the airor other uncondensable fluid to be delivered to the ejector E to beraised to higher pressure thereby.

For example, the suction chamber 1 of the ejector E may be connected bysuitable piping to a steam condenser in which the exhaust steam from anysuitable source, as for example, a steam turbine, is to be condensed andin which high vacuum is to be maintained. The ejector is provided withsuitable nozzle structure, as one or any suitable number of expansionnozzles N communicating with the steam or motive fluid chamber 2 anddirected toward the diffuser or combining tube structure D The motivefluid, as steam, is delivered from any suitable source, as a boiler, notshown, by pipe 3 which, in the example illustrated, has three branches,4, 5 and 6, provided, respectively, with the cut-off valves 7, 8 and 9.In the pipes 4 and 5 are interpolated, respectively, the nozzles ororifice plates 10 and 11. One of .these, as the nozzle or orifice platestructure 10 of pipe 4, is illustratedon larger scale in Fig. '3, whereit will be noted that the plate or member 12 is introduced betweenneighboring sections of the pipe 4: and is provided with the orifice ornozzle passage 10, of fixed dimensions and allowing generally passage,in the direction of the arrow, at a predetermined motive fluid pressurein the pipe "3, of a predetermined-amount of motive fluid. The secondstage ejector E is provided with nozzle structure comprising one or anysuitable number of expansion nozzles N communicating with the steamchamber 13, between which and the motive fluid supplypipe 14 are threebranches 15, 16 and 17 I rovided, respectively, with the shut-ofl' vaves 18, 19 and 20,. and two of the branches, 15 and 16, being provided,re-' spectively, with orifices or nozzles 21 and 22.

Assuming that the interstage condenser C is absent and that the ejectorE discharges more or less directly to the suction chamber of the ejectorE with the valves7 and 8 of the first stage and 18 and 19 of the secondstage c-losed, and the valves 9 and 20 open, full pressure of the motivefluid is applied to the nozzle structures of both stages."

Further assuming that this motive fluid pressure. is the 'same asapplied to both stages through the branches 6 and 17, the ejector willor may have a characteristic resembling the characteristic curve A ofFig. 1. If now it is desired to work at a lower absolute pressure in thesuction chamber 1 of the ejector E, the valves 8 and 9 are closed, andthe valve 7 opened, whereby there then intervenes between the steam pipe3 and the steam chamher 2 the nozzle or orifice 10, which accordinglythrottles the motive fluid steam so that instead of having, as before,practically 125 pounds pressure upon the steam chamber 2,

the pressure will now be less and will be, for

example, 100 pounds per square inch. Under these conditions, and withvalve 20 open and valves 18 and 19 closed, the performance will be ofthe character indicated by the curve B of Fig. 1, whereby at lowerabsolute pressures inv the suction chamber l-of the ejector. E greateramounts of air or other fluid entering the suction chamber 1 will becompressed to the desired final pressure at the discharge of thediffuser D of the sec- 0nd stage, with lower steam pressure upon thefirst stage nozzle structure and consumption of less motive steam.Again, if it is desired to work at still lower absolute pressure in thesuction chamber 1, the valve 7 is closed, the valve 9 remains closed,and the valve 8 opened, the valves of the second stage nozzle structureremaining as before. In this case there intervenes between the steampipe 3 and the steam chamber 2 the second or smaller orifice or nozzle11, with the result that there exist-s in the steam chamber 2 a pressureof, for example, 85 pounds per squareinch, in which case the performancewill be of the character indicated by the curve C, Fig. 1, whereby stillless motive fluid pressure is employed, less amount of motive fluid isemployed, and relatively greater amount of air or other fluid isentrained and compressed. While with the above described operation thevalve 20 of the second stage is open while the valves 18,and 19 areclosed, the performance can be still further improved by employing inconnection with the second stage the nozzles 21 and 22, which have, asregards the second stage, and as regards the over-all performance ofboth stages, eifects similar to those above described in connection withFig. 1. My invention is, however, of more importance in connection withthe first stage, since at the discharge of the diffuserD of the firststage the back pressure of the first stage varies with the load oramount of air or fluid to be entrained or compressed, while as regardsthe second stage the pressure at the discharge of the difl'user D isgenerally substantially constant.

When any one of the three branches 4, 5 or 6 of the first stagestructure is employed, any one of the three branches 15,

16 or 17 of the second stage structure may.

beemployed.

. It willbe further understood as to the first stage. and also as to thesecond stage, that the branches 6 and 17 may be considered by-passes forthe nozzles or orifices 10, 11 and 21, 22. It will be understood,however, that these by-passes may be omitted, and when highest pressureis to be available upon the steam chambers 2 and 13, the nozzles 10, 11and (or) 21, 22' may be simultaneously in operation.

In general, it is preferred to employ an interstage condenser betweenthe two stages of the ejector apparatus for condensing out from themixture discharged from the first stage all condensable vapors, as themotive steam and any condensable'vapors in the entrained fluid.

When an interstage condenser is employed between the first and secondstage ejectors, the employment of the motive fluid pressure-changingmeans, particularly of the first stage ejector, is of greater advantagethan when no interstage condenser is employed. This is due to the factthat when an interstage condenser is employed, the pressure at thedischarge of the first stage ejector varies through a greater range forgiven variations in the weights or amounts of fluid to be entrained andcompressed.

Referring to Fig. 4, there is shown in the first stage an ejectorE, ingeneral of any suitable character, as a tubular ejector, and such, forexample, as the ejector E of Fig. 2. In the second stage the ejector Eis provided with an annular nozzle N producing a circular sheet or jetof motive fluid which entrains the fluid discharged from the first stageejector E, and the mixture is delivered into the surrounding annulardiffuser D and delivered intothe discharge casing F, from which it isdischarged through the port F In this case the ejector E is'providedwith the branches 4, 5 and 6, as in Fig. 2.

The, combination of ejector E with ejector E is of the eneral characterdisclosed in prior Letters l atent of the United States No. 1,282,595.This combination affords a. perfectly stable operation throughout greatvariations of, load or amounts of fluid to be entrained and compressedand throughout great ranges of change of pressure in the first stagesuction chamber 1. However, it is of advantage to apply to the firststage ejector of such combination the means for varyin the motive fluidpressure for obtaining the effects hereinbefore described.

While the second stage ejector E of Fig. 4 is shown as supplied withmotive fluid at full boiler pressure, it will be understood that themotive fluid for the second stage nozzle structure N may be similarlythrottled, though in general this will not be necessary or of greatadvantage.

While I have in Figs. 2 and 4 shown two nozzles or orifices between thesteam supply and the steam chamber of each stage, it will .be understoodthat any other suitable number of orifices may be employed.

From the foregoing description it is apparent that while the nozzlestructure of ejector apparatus has constant ratio of expansion, that is,the ratio of throat area to outlet area of the nozzle structure isconstant, improved performance for different suction pressures isavailable by suitably changing the pressure of the motive fluid su pliedto that nozzle structure.

hile, as illustrated and preferred, orifices or nozzles are employed foreffecting changes in-the motive fluid pressure as applied to the nozzlestructures, it will be understood that any equivalent means may beemployed, as for example, valve structure, if capable of being set-topredetermined positions or openings. It will be understood, of course,that the valves 7, 8, 9 and 18, 19, 20 are ordinary shut-ofl' valveswith which it is difficult or impossible to procure any predetermined orproper adjustments for pressure determination.

What I claim is:

1. The method of compressing elastic fluid by elastic motive fluid,which consists in expanding motive fluid into jet formation, entrainingthereby the fluid to becompressed, converting the velocity of themixture into pressure, and controlling the characteristic of theoperation by giving to the motive fluid in advance of the aforesaid jetpanding motive fluid into jet formation,

. entraining. thereby the fluid to be. compressed, converting thevelocity of the mixture into pressure, and controlling thecharacteristic of the operation by throttling the motive fluid inadvance of the aforesaid jet formation to different predetermineddegrees.

3. The method of compressing elastic fluid in a plurality of stages,which consists in expanding motive fluld into jet formation, entrainingthereby the fluid to be compressed, converting the velocity ofthemixture into pressure, giving to the motive fluid in. advance of theaforesaid jet formation different definite or predetermined pressures,

expanding in a later stage motive fluid intojet formation, entrainingfluid of the afore said mixture thereby, and converting veloc-.

thereby the uncondensed component of said mixture, and convertingvelocity of the mixture'into pressure.

5. Ejector apparatus comprising expasion nozzle structure, co-operatingdiffuser structure, means for conveying motive fluid to said nozzlestructure, means for diminishing the pressure of said motive fluid topredetermined degree, and means for by passing said last named means.

6. Ejector apparatus comprlsing expansion nozzle structure, co-operatingdiffuser structure, and a plurality of means for reducing the pressureof the motive fluid delivered to said nozzle structure to differentdegrees. 1

7. Ejector apparatus comprising expansion nozzle structure, co-operatingdiffuser structure, meansfor conveying motive fluid to said nozzlestructure, means for diminish ing the pressure of said motive fluid topredetermined degree, means for by-passing said last named means, andvalve structure for controlling said pressure diminishing means.

8. Plural stage ejector apparatus comprising in each stage nozzlestructure and cooperating difl'user structure, and means for throttlingto predetermined degree the motive fluid delivered to the nozzlestructure of one of said stages.

9. Plural stage ejector apparatus comprising in each stage nozzlestructure and cooperating diffuser structure, and means for each stagefor throttling the motive fl uid delivered to the nozzle gtructurethereof to predetermined degree;

10. Thecombination with staged ejectors, of interstage condenserstructure, and means for throttling to predetermined degree the motivefluid delivered to the nozzle structure of the ejector discharging intosaid 'condenser structure.

11. The combination with staged ejectors, I

of interstage condenser structure, means for throttling to predetermineddegree the motive fluid delivered to the nozzle structure of the ejectordischargin into said condenser structure, and means. or throttling topredetermined degree the motive fluid delivered to the nozzle structureof an ejector receiving the discharge from said condenser structure.

prising a plurality of staged ejectors, interstage condenser structure,and a plurality of means for throttling to different predeter-'mined'degrees the motive fluid delivered to one of said ejectors.-

l3. Plural stage ejector apparatus com- 12. Pluralstage ejectorapparatus comprising a plurality of staged ejectors, interstagecondenser structure, and a plurality of means for throttling todifferent predetermined degrees the motive fluid delivered to the nozzlestructure of one of said ejectors discharging into said condenserstructure.

14. Ejector apparatus comprising nozzle structure, co-o erating diffuserstructure, means for con uctino motive fluid'to said ejector, and amember disposed between said means and said nozzle structure'having anorifice of predetermined area for diminishing the pressure of the motivefluiddelivered to said nozzle structure.

1'5. Ejector apparatus comprising nozzle structure and cooperatingdiffuser structurgi means for delivering motive fluid to sai ejector, aplurality of throttling members having orifices of diflerent areas, andmeans for connecting said orifices in operative relation with saidnozzle structure.

16. The method of compressing elastic fluid in a plurality of stages,which consists in expanding motive fluid into jet formation, entrainingthereby the fluid to be compressed, converting the velocity of themixture into pressure, expanding in a later stage motive fluidinto jetformation, entraining thereby fluid of'the aforesaid mixture, convertingvelocity of the resultant mixture into pressure, and changing thecharacteristic of operation by changing to predetermined pressure saidsecond named motive fluid in advance of said second named jet formation.

17. The method of compressing elastic fluid in a plurality of stages,which consists in expanding motive fluid into jet formation,

entraining thereby the fluid to be com-- pressed, converting thevelocity of the mixture into pressure, condensing the condensablecomponent 'of pressure sai said mixture, expanding motive fluid inanother stage into jet formation, entraining thereby the uncondensedcomponent of said mixture, converting the" velocity of the resultantmixture into pressure, and changing the characteristic of the operationb changing to predetermined second named motive fluid in advance of saidsecond named jet formation.

18. The method of operating ejector apparatus utilizing expanded elasticmotive fluid for compressing elastic fluid, which consists in changingto predetermined extent the pressure of the elastic fluid beforeexpansion in accord with the initial pressure of the elastic fluid to becompressed.

19. The combination wi h ejector apparatus comprising nozzle structurehaving constant throat area and expansion ratio for expanding elasticmotive fluid, and c'o-operating diffuser structure, of means forchanging the operatin characteristic comprising means for changmg topredetermined extent the pressure of the motive fluid delivered to saidnozzle structure.

20. Plural stage ejector apparatus comprising an ejector, means forchanging the pressure of the elastic m'otive fluid delivered to saidejector from one predetermined'pressure to another, and a second ejectorto which is delivered fluid by said first named ejector for furthercompression by said second ejector.

In testimony whereof I have hereunto af- I fixed my signature this 9thday of May, 1921.

- ROBERT SUOZEK.

